"Large-scale fire tests conducted in a number of countries and observations of actual building fires have shown that the fire performance of composite steel framed buildings is much better than is indicated by fire resistance tests on isolated elements. It is clear that there are large reserves of fire resistance in modern steel-framed buildings and that standard fire resistance tests on single unrestrained members do not provide a satisfactory indicator of the performance of such structures.

The Design Guide presents guidance on the application of a simple design method, as implemented in FRACOF software, that has been developed as a result of observation and analysis of the BRE Cardington large-scale building fire test programme carried out during 1995 and 1996. The recommendations are conservative and are limited to structures similar to that tested, i.e. non-sway steel-framed buildings with composite floors. The guidance gives designers access to whole building behaviour and allows them to determine which members can remain unprotected while maintaining levels of safety equivalent to traditional methods.

In recognition that many fire safety engineers are now considering natural fires, a natural fire model is included alongside the use of the standard fire model, both expressed as temperature-time curves in Eurocode 1.

In addition to the Design Guide, a separate Engineering Background document provides details of fire testing and finite element analysis conducted as part of the FRACOF project and some details of the Cardington tests which were conducted on the eight-storey building at Cardington. The background document will assist the reader to understand the basis of the design recommendations in this publication."